Eric Miller said the big idea behind SmartTrack is to connect Torontonians to three major employment centres in the region — the downtown, said Miller, as well as "very excitingly, also to Markham and the Airport Corporate Centre."

The University of Toronto transit expert said the plan is revolutionary because, for the first time, it creates two-way traffic on existing railway right-of-ways, without, for the most part, the cost of tunnelling because most of the proposed system is surface rail.

Particularly appealing is the focus on electrified rail technology, which Miller calls "state of the art for high-quality, long-distance commuter rail."

Miller calls it a transit plan that "connects the dots between people and jobs in a way that other plans developed for political purposes don't."

The trains are also expected to have very high ridership numbers, and could even cover most of the operating costs out of the fare box, said Miller.

"It's not just people coming downtown and empty trains going back out," says Miller. "The trains will be loaded both ways so the revenue potential is very strong. It may well make money on an operating basis."

Eric Miller stands in the Transportation Lab at University of Toronto. (University of Toronto)

It also has the added benefit, Miller predicts, of relieving crowding on the Yonge subway line, and would reduce the urgency for the proposed Downtown Relief Line, possibly even eliminating the need for the relief line altogether.

SmartTrack would run from Markham, on the east side of York Region, south through Scarborough, giving passengers in the north and east an alternative to the subway trains, which are often full southbound by the time they leave Finch Station every morning.

The alternative route would also relieve dangerous overcrowding at the transfer station at Bloor-Yonge, which currently creates many problems and delays.

"It offers those passengers an express trip into the downtown," says Miller. "They'll never have to touch Yonge Street, freeing up capacity for people from North York and elsewhere who would still use the subway."

SmartTrack has come under attack because tunnelling costs along sections of the network are unknown, especially around Eglinton Avenue West.

But according to Miller, the more important thing is whether or not SmartTrack is a good idea.

"If you look at the entire line and how much service you're getting at what price, and if we have to spend some money tunnelling, it's well worth the effort."

Miller says many of the attacks on SmartTrack are politically motivated.

"No one asks the same questions about the Downtown Relief Line," said Miller. "And no one knows what that's going to cost. No one knows the technical challenges of that. So I think there's been a lot of micromanaging by wanna-be engineers. They can't criticize the concept of the line so they have to find something to criticize."

Grading: "I'd give it an A-plus," said Miller. "It's the best thing I've seen in years. It's going to make Eglinton Crosstown better. It's going to make Bloor-Danforth better. It's going to make Yonge Street better. It's going to make buses better. It's going to connect so many things that it will really make a difference."

Paul Bedford is a former city planner and former director of Metrolinx.

He is also a fan of SmartTrack, noting it will connect large parts of Toronto.

"It is a bold and powerful concept that has captured the imagination of the public. It connects a total of approximately 100-million square feet of ‎urban and suburban office employment with a single transit line that has huge two-way ridership potential," he said.

"It can also provide considerable relief to Yonge-Bloor since it would divert a large number of riders originating in the east, away from the Danforth subway."

"While the use of Tax Increment Financing (TIF) is a valid tool," he said, "I believe other revenue sources will also be needed."

Grading: "I would give John Tory's transit plan an A-minus," said Bedford.

Murtaza Haider is an associate professor at Ryerson University's Ted Rogers School of Management, specializing in transportation management.

He called Tory’s plan "creative in capturing the latent capacity in the existing rail tracks within and around Toronto."

"Building relatively more frequent rail service on existing tracks is significantly cheaper than building new subways from scratch," he said.

He also noted the connectivity of resident and employment hubs in the Greater Toronto Area.

"Mr. Tory’s plan is likely to emerge as a viable, long-term solution to improve mobility in the region," said Haider.

However, the issue of financing seems to bother Haider.

Tory claims TIF will pay for the city’s share of the capital costs of $8 billion in transit improvements.

But recent experience with TIF projects in New York and Chicago suggests that it works primarily in blighted areas "where land values have room to grow," he argued. "At the same time, TIF-based properties are more expensive and are known to worsen housing affordability. Lastly, and more importantly, the New York 7 subway project shows that TIF can fall significantly short of raising projected revenue."

Haider also pointed out there will be no relief for transit riders for an entire mayoral term.

And, he added, Tory is like his opponents in that he ignores service improvements on the Yonge-University-Spadina line, which he said is operating 30 per cent below capacity during rush hour. He said this line needs attention.

He also faulted Tory for abandoning his support for a downtown relief line, calling it a mistake to overlook the proposed line.